This invention relates to a control, or manipulation, element for control functions within a passenger area of a vehicle having a plurality of tuning knobs whose positions are indicated by an illumination display, including an LED (Light Emitting Device) and a light-guide, in which a turning knob includes the light guide that is coupled directly with the LED and has a light-exit surface that is coupled with a light-entry surface leading to the other turning knobs
Control elements of this type are required, for example, for the control functions of air conditioning or ventilation equipment. Indexing of a turning knob in intermediate positions is required, particularly for adjusting temperatures, with end positions being held more securely.
Conventional indexing devices in the prior art (German patent document DE295 01 692 U1) have snapping elements such as spring balls, leaf springs, etc., that result in a significant load on bearings, etc., causing, in addition to wear, undue binding of the turning knob.
It is an object of this invention to provide a sensitive indexing of a turning knob of this type without requiring an undue increase in an adjusting force.
According to principles of this invention a light guide is connected to a turning knob and has, on axial surfaces at an outer rim, indexing bumps and indexing indentations, respectively, that cooperate with retaining catches of a retaining spring that is pushed onto a light-conducting plate within retaining ribs and is locked between an edge of the light-conducting plate and a housing rib in the pushed-on direction.